<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <Header ref="head"></Header>
        <List
          :num="123"
          :todos="todos"
          :deleteTodo="deleteTodo"
          :updateTodo="updateTodo"
        ></List>
        <Footer
          :todos="todos"
          :updateAll="updateAll"
          :deleteTodos="deleteTodos"
        ></Footer>
      </div>
    </div>
  </div>
</template>

<script>
import Header from "@/components/Header";
import List from "@/components/List";
import Footer from "@/components/Footer";

export default {
  name: "App",
  components: {
    Header,
    List,
    Footer,
  },
  data() {
    return {
      todos: JSON.parse(localStorage.getItem("todos")) || [],
    };
  },
  watch: {
    // 只要todos发生变化，就会执行这个函数
    // 只要执行这个函数就可以将数据进行本地存储
    todos: {
      handler(newVal, oldVal) {
        console.log(newVal,oldVal);
        localStorage.setItem("todos", JSON.stringify(newVal));
      },
      deep: true,
      immediate: true,
    },
  },
  methods: {
    addTodo(todo) {
      this.todos.unshift(todo);
    },
    deleteTodo(index) {
      this.todos.splice(index, 1);
    },
    updateTodo(index) {
      this.todos[index].completed = !this.todos[index].completed;
    },
    updateAll(val) {
      this.todos.forEach((todo) => (todo.completed = val));
    },
    deleteTodos() {
      this.todos = this.todos.filter((todo) => todo.completed === false);
    },
  },
  mounted() {
      this.$refs.head.$on('addTodo',this.addTodo);
      console.log(this.$refs.head);
  }
};
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}
</style>
<style scoped lang="less">
// 需要实现深度样式选择,或者叫穿透样式操作
.todo-header ::v-deep input {
  background: #f5f5f5;
}
/*app*/
.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>
